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Medline ® Abstract for Reference 34

of 'Breast conserving therapy'

Pathologic margin involvement and the risk of recurrence in patients treated with breast-conserving therapy.
Gage I, Schnitt SJ, Nixon AJ, Silver B, Recht A, Troyan SL, Eberlein T, Love SM, Gelman R, Harris JR, Connolly JL
Cancer. 1996;78(9):1921.
BACKGROUND: The relationship between the microscopic margins of resection and ipsilateral breast recurrence (IBR) after breast-conserving therapy for carcinomas with or without an extensive intraductal component (EIC) has not been adequately defined.
METHODS: Of 1,790 women with unilateral clinical Stage I or II breast carcinoma treated with radiation therapy as part of breast-conserving therapy, 343 had invasive ductal histology evaluable for an extensive intraductal component (EIC), had inked margins that were evaluable for an review of their pathology slides, and received>or = 60 Gray to the tumor bed; these 343 women constitute the study population. The median follow-up was 109 months. All available slides were reviewed by one of the study pathologists. Final inked margins of excision were classified as negative>1 mm (no invasive or in situ ductal carcinoma within 1 mm of the inked margin); negative-1 mm, or close carcinoma<or = 1 mm from the inked margin but not at the margin); or positive (carcinoma at the inked margin). A focally positive margin was defined as invasive or in situ ductal carcinoma at the margin in three or fewer low-power fields. The firstsite of recurrent disease was classified as either ipsilateral breast recurrence (IBR) or distant metastasis/regional lymph node failure.
RESULTS: Crude rates for the first site of recurrence were calculated first for all 340 patients evaluable at 5 years, then separately for the 272 patients with EIC-negative cancers and the 68 patients with EIC-positive cancers. The 5-year rate of IBR for all patients with negative margins was 2%; and for all patients with positive margins, the rate was 16%. Among patients with negative margins, the 5-year rate of IBR was 2% for all patients with close margins (negative<or = 1 mm) and 3% for those with negative>1 mm margins. For patients with close margins, the rates were 2% and 0% for EIC-negative and EIC-positive tumors, respectively; the corresponding rates for patients with negative margins>1 mm were 1% and 14%. The 5-year rate of IBR for patients with focally positive margins was 9% (9% for EIC-negative and 7% for EIC-positive patients). The 5-year crude rate of IBR for patients with greater than focally positive margins was 28% (19% for EIC-negative and 42% for EIC-positive patients).
CONCLUSIONS: Patients with negative margins of excision have a low rate of recurrence in the treated breast, whether the margin is>1 mm or<or = 1 mm and whether the carcinoma is EIC-negative or EIC-positive. Among patients with positive margins, those with focally positive margins have a considerably lower risk of local recurrence than those with more than focally positive margins, and could be considered for breast-conserving therapy.
Joint Center for Radiation Therapy, Beth Israel Hospital, Harvard, Medical School, Boston, Massachusetts 02215, USA.